1. Field of the Invention
This invention relates in general to hydraulic couplings, and specifically to hydraulic couplings used in undersea drilling and production applications. More particularly, this invention involves a hydraulic coupling member with a reduced probe diameter and flow ports in the probe configured to prevent ingress of debris into the hydraulic system.
2. Description of Related Art
Subsea hydraulic couplings are old in the art. The couplings generally consist of a male member and a female member with sealed fluid passageways connecting therebetween. The female member generally is a cylindrical body with a relatively large diameter longitudinal bore at one end and a relatively small diameter longitudinal bore at the other. The small bore facilitates connections to hydraulic lines, while the large bore seals and slidingly engages the male member of the coupling. The male member includes a cylindrical portion at one end having an outer diameter approximately equal to the diameter of the large bore in the female member of the coupling. The male member also includes a connection at its other end to facilitate connection to hydraulic lines. When the cylindrical portion of the male member is inserted into the large bore of the female member, according to various embodiments of the device, fluid flow is established between the male and female members. Several couplings of this type are shown in patents owned by National Coupling Company, Inc. of Stafford, Tex.
In undersea drilling and production applications, the male member of the coupling may be connected to a manifold plate or other securement at a subsea location at the inside or outside of a well bore. In many cases, the male members are positioned so that the end or leading face of each member points vertically up from the sea floor. The female members, which also may be secured to a manifold plate, are moved into position over the male members and then lowered onto the male members by a diver or subsea vehicle, such as an ROV (remote operating vehicle). When the female members are positioned on the male members, hydraulic fluid flow typically is from the female member to the male member of each coupling. Typically, one or both of the coupling members have poppet valves.
Each poppet valve typically includes a conical valve face which seats, in the closed position, against a valve seat in the coupling member. The poppet valve opens to allow fluid flow, and closes against the valve seat within the bore to arrest the flow. Generally, the poppet valve is spring-biased to the closed position. The valve may include a valve actuator which may be a nose or stem extending from the apex of the valve face along the longitudinal axis of the poppet valve.
Frequently, well bores in which the couplings are positioned contain debris. The male member, which remains subsea when the coupling is disconnected, is subject to debris accumulating in exposed flow passages when it is disconnected from the female member. The debris may contaminate the hydraulic fluid or cause wear to the seals and sealing surfaces in the hydraulic couplings and hydraulic system.
Exposed flow passages in the male coupling member may be adjacent the end or leading face of the probe section, male coupling member. Additionally, when the poppet valve is positioned intermediate the male member, debris could accumulate in that portion of the male member between the leading face and the poppet valve, sometimes referred to as the probe section. For example, in couplings having the poppet valve in the body section, there is a risk of accumulating debris in the probe section when the poppet valve is closed. A coupling member is needed to prevent the debris from accumulating in the probe section, to prevent such debris from entering the hydraulic lines, and to prevent interference with the valve actuator which extends from the poppet valve.
In U.S. Pat. No. 5,692,538 to Robert E. Smith III, assigned to National Coupling Company, Inc., an undersea hydraulic coupling member is shown having angled flow passages in the body of the male member to help prevent ingress of debris. When the female member is attached to the male member, hydraulic pressure through the angled flow ports and against the face of the poppet valve urges the poppet valve of the male member open to allow fluid to flow between the coupling members. The poppet valve in combination with the angled flow ports in the male member body help prevent ingress of debris, while allowing trapped hydraulic fluid pressure to bleed off when the coupling members are disconnected.
Recently there is a need for undersea hydraulic couplings in extremely deep water systems. It is desirable to reduce the size and weight of each coupling member for such systems. For example, it is desirable to reduce the diameter of the probe section of the male member, thus reducing the size and weight of the coupling member. However, the need remains to maintain high flow rates of hydraulic fluid through the coupling members and hydraulic system of which the coupling is a part. An undersea hydraulic coupling also is needed that will help prevent debris and other particles from entering the hydraulic lines.